US3880599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control of rod diameter responsive to a plurality of corrected parameters
Assignee: Siemens AG
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Filing: 1973-03-19
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Granted: 1975-04-29
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Expires: 1993-03-19
Abstract
Abstract A method for controlling the course of a floating melting zone process, in which a melting zone is electromagnetically induced in a semiconductor rod includes the steps of monitoring the r.f. frequency of the signal applied to induce heating in the rod, monitoring the voltage drop across the induction heating coil, and monitoring the current drawn by the r.f. generator, and controlling, in response to these three variables, the frequency of the signal and the velocity at which the silicon rod is pulled, in order to bring all three of the independent variables into agreement with desired values, to produce a rod of a constant desired diameter.
Inventors
- 👤 Wolfgang Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:23
CPC Classifications
C; C30; C30B; C30B13/00; C30B13/28; C30B13/30; Y; Y10; Y10T; Y10T117/00; Y10T117/10; Y10T117/1004; Y10T117/1008
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
134 words
A METHOD FOR THE CONTROL OF A FLOATING ZONE MELTING PROCESS IN WHICH A ZONE IN A SEMICONDUCTOR ROD IS HEATED INDUCTIVELY BY MEANS OF R.F. ENERGY SUPPLIED TO A COIL SURROUNDING THE ROD, AND INCLUDING DRIVE MEANS FOR MOVING THE HEATED ZONE LONGITUDINALLY THROUGH THE ROD, COMPRISING THE STEPS OF SENSING THE FREQUENCY OF SAID R.F. GENERATOR, SENSING THE CURRENT DRAWN BY SAID R.F. GENERATOR, ENSING THE VOLTAGE DROP ACROSS SAID COIL, COMPARING SAID FREQUENCY, CURRENT AND VOLTAGE WITH A REFERENCE FREQUENCY, CURRENT AND VOLTAGE RESPECTIVELY TO YEILD RESULTING PARAMTERS REPRESENTING THE RESPECTIVE ERRORS BETWEEN SAID RESULTING PARAMTERS THE FREAGES, AND CONTROLLING WITH SAID RESULTING PARAMTERS THE FREQUENCY OF SAID GENERATOR AND THE RELATIVE VELOCITY BETWEEN UPPER AND LOWER ROD HOLDER OF SAID DRIVE MEANS FOR PRODUCING A ROD HAVING A PREDETERMINED DIAMETER.
Claim 2
Independent Claim
134 words
A METHOD FOR THE CONTROL OF A FLOATING ZONE MELTING PROCESS IN WHICH A ZONE IN A SEMICONDUCTOR ROD IS HEATED INDUCTIVELY BY MEANS OF R.F. ENERGY SUPPLIED TO A COIL SURROUNDING THE ROD, AND INCLUDING DRIVE MEANS FOR MOVING THE HEATED ZONE LONGITUDINALLY THROUGH THE ROD, COMPRISING THE STEPS OF SENSING THE FREQUENCY OF SAID R.F. GENERATOR, SENSING THE CURRENT DRAWN BY SAID R.F. GENERATOR, ENSING THE VOLTAGE DROP ACROSS SAID COIL, COMPARING SAID FREQUENCY, CURRENT AND VOLTAGE WITH A REFERENCE FREQUENCY, CURRENT AND VOLTAGE RESPECTIVELY TO YEILD RESULTING PARAMTERS REPRESENTING THE RESPECTIVE ERRORS BETWEEN SAID RESULTING PARAMTERS THE FREAGES, AND CONTROLLING WITH SAID RESULTING PARAMTERS THE FREQUENCY OF SAID GENERATOR AND THE RELATIVE VELOCITY BETWEEN UPPER AND LOWER ROD HOLDER OF SAID DRIVE MEANS FOR PRODUCING A ROD HAVING A PREDETERMINED DIAMETER.
Claim 3
Dependent Claim
58 words
The method according to claim 1, including the step of periodically operating switch means to utilize a first pair of said resulting parameters, controlling said frequency and relative velocity in response to said first pair of parameters, thereafter choosing a second pair of parameters, and controlling said frequency and velocity in response to said second pair of parameters.
Claim 4
Dependent Claim
38 words
The method according to claim 2, including the step of repeatedly operating said switch means to utilize said first pair of parameters and then said second pair of parameters for the control of said frequency and relative velocity.
Claim 5
Dependent Claim
37 words
The method according to claim 3, including the step of periodically operating said switch means to utilize said second pair of parameters after said first pair of parameters have been brought into coincidence with predetermined values therefor.
Claim 6
Dependent Claim
37 words
The method according to claim 4, including the step of periodically operating said switch means to utilize said first pair of parameters after said second pair of parameters has been brought into coincidence with predetermined values therefor.
Claim 7
Dependent Claim
44 words
The method according to claim 1, including the steps of controlling the frequency of said generator in response to one of said three parameters, and controlling the relative velocity of said drive means alternately in response to the other two of said three parameters.
Claim 8
Dependent Claim
44 words
The method according to claim 1, including the steps of controlling the relative velocity of said drive means in response to one of said three parameters, and controlling the frequency of said generator alternately in response to the other two of said three parameters.
Claim 9
Dependent Claim
87 words
The method according to claim 1, including the step of periodically operating switch means to utilize first and second ones of said three parameters, controlling the frequency of said generator in response to said first parameter and simultaneously controlling the velocity of said drive means in response to said second parameter, and cyclically utilizing different pairs of said three parameters, whereby either said frequency or said relative velocity or both is controlled in response to a different parameter during each cycle than in the next previous cycle.
Claim 10
Dependent Claim
40 words
The method according to claim 8, including the step of initiating a new cycle by utilizing a different pair of said parameters when the parameters chosen during the next previous cycle have been brought into coincidence with described values therefor.
Claim 11
Independent Claim
114 words
A method for controlling a complex process having first and second control means for controlling two parameters in said process and first, second and third sensing means for sensing three parameters which are interrelated with each other, including the steps of comparing said three sensed parameters with three reference parameters representing the respective errors between said respective sensed and reference parameters, to yield resulting parameters, cyclically utilizing different pairs of saiD resulting parameters, and operating said first and second control means in response to the pair of resulting parameters utilized at any given time. and operating said first and second control means in response to the pair of parameters selected at any given time.
Claim 12
Independent Claim
114 words
A method for controlling a complex process having first and second control means for controlling two parameters in said process and first, second and third sensing means for sensing three parameters which are interrelated with each other, including the steps of comparing said three sensed parameters with three reference parameters representing the respective errors between said respective sensed and reference parameters, to yield resulting parameters, cyclically utilizing different pairs of saiD resulting parameters, and operating said first and second control means in response to the pair of resulting parameters utilized at any given time. and operating said first and second control means in response to the pair of parameters selected at any given time.
Claim 13
Dependent Claim
20 words
The method according to claim 10, wherein at least one of said controlled parameters is one of said sensed parameters.
Claim 14
Dependent Claim
19 words
The method according to claim 10, wherein at least one of said controlled parameters is not a sensed parameter.
Claim 15
Dependent Claim
176 words
Apparatus for controlling a complex process comprising, in combination; first and second control means for controlling two parameters in said process, first, second and third sensing means for producing signals responsive to three different parameters in said process, means for producing three signals representative of desired values for said three sensed parameters, means for producing three signals each representative of the difference between one of said three sensed parameters and its desired value, a double pole-triple throw switch means having the three stator terminals of one pole connected with said three difference signals to select one of said difference signals for connection to said first control means, said second control means being connected through the second pole of said double pole-triple throw switch to one of three lines, and a triple pole-double throw switch having its common terminals connected with said three lines and having its stator terminals connected with said three difference signals to select either two of said three difference signals other than said one difference signal for connection to said second control means.
Claim 16
Dependent Claim
176 words
Apparatus for controlling a complex process comprising, in combination; first and second control means for controlling two parameters in said process, first, second and third sensing means for producing signals responsive to three different parameters in said process, means for producing three signals representative of desired values for said three sensed parameters, means for producing three signals each representative of the difference between one of said three sensed parameters and its desired value, a double pole-triple throw switch means having the three stator terminals of one pole connected with said three difference signals to select one of said difference signals for connection to said first control means, said second control means being connected through the second pole of said double pole-triple throw switch to one of three lines, and a triple pole-double throw switch having its common terminals connected with said three lines and having its stator terminals connected with said three difference signals to select either two of said three difference signals other than said one difference signal for connection to said second control means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |